tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1Audio-Graph-SCU-Card:
2
3Audio-Graph-SCU-Card is "Audio-Graph-Card" + "ALSA DPCM".
4
5It is based on common bindings for device graphs.
6see ${LINUX}/Documentation/devicetree/bindings/graph.txt
7
8Basically, Audio-Graph-SCU-Card property is same as
9Simple-Card / Simple-SCU-Card / Audio-Graph-Card.
10see ${LINUX}/Documentation/devicetree/bindings/sound/simple-card.txt
11 ${LINUX}/Documentation/devicetree/bindings/sound/simple-scu-card.txt
12 ${LINUX}/Documentation/devicetree/bindings/sound/audio-graph-card.txt
13
14Below are same as Simple-Card / Audio-Graph-Card.
15
16- label
17- dai-format
18- frame-master
19- bitclock-master
20- bitclock-inversion
21- frame-inversion
22- dai-tdm-slot-num
23- dai-tdm-slot-width
24- clocks / system-clock-frequency
25
26Below are same as Simple-SCU-Card.
27
28- convert-rate
29- convert-channels
30- prefix
31- routing
32
33Required properties:
34
35- compatible : "audio-graph-scu-card";
36- dais : list of CPU DAI port{s}
37
38Example 1. Sampling Rate Conversion
39
40 sound_card {
41 compatible = "audio-graph-scu-card";
42
43 label = "sound-card";
44 prefix = "codec";
45 routing = "codec Playback", "DAI0 Playback",
46 "codec Playback", "DAI1 Playback";
47 convert-rate = <48000>;
48
49 dais = <&cpu_port>;
50 };
51
52 audio-codec {
53 ...
54
55 port {
56 codec_endpoint: endpoint {
57 remote-endpoint = <&cpu_endpoint>;
58 };
59 };
60 };
61
62 dai-controller {
63 ...
64 cpu_port: port {
65 cpu_endpoint: endpoint {
66 remote-endpoint = <&codec_endpoint>;
67
68 dai-format = "left_j";
69 ...
70 };
71 };
72 };
73
74Example 2. 2 CPU 1 Codec (Mixing)
75
76 sound_card {
77 compatible = "audio-graph-scu-card";
78
79 label = "sound-card";
80 prefix = "codec";
81 routing = "codec Playback", "DAI0 Playback",
82 "codec Playback", "DAI1 Playback";
83 convert-rate = <48000>;
84
85 dais = <&cpu_port0
86 &cpu_port1>;
87 };
88
89 audio-codec {
90 ...
91
92 port {
93 codec_endpoint0: endpoint {
94 remote-endpoint = <&cpu_endpoint0>;
95 };
96 codec_endpoint1: endpoint {
97 remote-endpoint = <&cpu_endpoint1>;
98 };
99 };
100 };
101
102 dai-controller {
103 ...
104 ports {
105 cpu_port0: port {
106 cpu_endpoint0: endpoint {
107 remote-endpoint = <&codec_endpoint0>;
108
109 dai-format = "left_j";
110 ...
111 };
112 };
113 cpu_port1: port {
114 cpu_endpoint1: endpoint {
115 remote-endpoint = <&codec_endpoint1>;
116
117 dai-format = "left_j";
118 ...
119 };
120 };
121 };
122 };